1. Download ZIP from https://github.com/nodemcu/nodemcu-flasher and extract.
2. Download Nodelua Firmware
3. Set ESP8266 to flashmode (Connect GPIO0 to GND + don’t forget to share GND of Powersupply and Serial adapter if they are not the same device)
4. Run ESP8266Flasher.exe from Win32 or Win64/Release
5. Go to Config , only select the first entry with 0x00000 Offset and select the Nodelua Firmware.
6. Go back to Operation, select COM Port and click Flash and Wait and put ESP back to normal mode